This work can be extended to construct a conformal scattering theory for the Fackerell-Ipser equations on the other symmetric spherical spacetimes (such as Reissner-Nordström-de Sitter back hole) can be done by the same way: first, by extending the work [1]} to obtain the decay results (where the results of Giorgi [2]} can be useful) and then using these results to the construction of the theory, where it remains useful to use the time-like Killing vector field \(\partial _t\)  to obtain the energy of the fields.
